1 · What to calculate, and where
Choose the project type(s), pick a location, then pull 10 years of climate.
Data sources & history
Off by default: Open-Meteo (native FAO-56 ET₀) and NASA POWER (ET₀ via Penman-Monteith) are free, fast, and cover the full 10 years. Tomorrow.io is slow (fetched in 30-day windows, its API limit) and on many plans returns no historical ET₀, so it's only used if it actually adds ET₀ — and it's capped at 90 seconds so it can't hang the run. Use the Test button before turning it on. The key is embedded in this file — anyone you share the file with can use it, so rotate it if that's a concern.
2 · Crop & crop coefficient (Kc)
Search a crop to see its Kc table, then pick it. Values are mapped onto your irrigation season and stay editable.
3 · Irrigation systems & efficiency
Set the efficiencies for each project. Every value is editable.
4 · Water savings target
How much water do you need to save per year? Enter it in million gallons (MG).
Converted to m³ internally (1 MG = 3,785.41 m³); results shown in metric and imperial.
5 · Results
The Excel file holds the raw daily weather, the monthly aggregation, the water balance, and separate N-Drip / Connect sheets — all as live formulas with editable inputs (Kc, season, efficiencies, target). Calculations are metric; results are shown in all units.
6 · Literature
Have Claude research the published irrigation figures for your crop and location, then bring the table back here to sit next to your calculation.
Step 1 — copy this prompt into Claude
Paste it into a Claude chat with web search on. Claude finds real papers, reads them, and returns a table plus a data block to paste back below.
Step 2 — paste Claude's data block back here
Definitions used everywhere here (mm per season):
ETc — crop evapotranspiration, Kc × ET₀: the crop's total water demand.
NIR — net irrigation requirement, ETc − effective rainfall: what irrigation must supply, before system losses.
GIR — gross irrigation requirement, NIR ÷ system efficiency: the depth actually applied in the field. Most papers reporting "irrigation applied" mean this.
CU — consumptive use, applied × (1 − return flow): water consumed rather than returned to the source. Many papers treat CU as a synonym for ETc — when a source does, the value belongs in the ETc column.
Compare like with like, and open the link before relying on any figure.
ETc — crop evapotranspiration, Kc × ET₀: the crop's total water demand.
NIR — net irrigation requirement, ETc − effective rainfall: what irrigation must supply, before system losses.
GIR — gross irrigation requirement, NIR ÷ system efficiency: the depth actually applied in the field. Most papers reporting "irrigation applied" mean this.
CU — consumptive use, applied × (1 − return flow): water consumed rather than returned to the source. Many papers treat CU as a synonym for ETc — when a source does, the value belongs in the ETc column.
Compare like with like, and open the link before relying on any figure.